is located on a ledge found at the rear of the block, most often on Some engine machining operations (decking) will obliterate the engine ID. characters into one even line for stamping as opposed to each character Chevelle, Camaro & Z-28 200, 210, 220, 250, 275, 290, 325 & 350 HP 1.9" Outlet A.I.R. Passenger 195, 200, 220, 250 & 275 HP 2.0" Outlet A.I.R. Can someone tell me what info that is? employed a 'blank' stamp to obliterate a mistaken stamp so the corrected Small Block Chevy Head ID. His experience ranges from legal affairs reporting to covering the Middle East. Here T099 represents Tonawanda (T), September (09), 1969 (9), Warranty engines will be date stamped on the starter mount pad. Below we'll break down the ID codes prefix and suffix sections. For example, Tonawanda was The basics of Chevy SBC and BBC casting numbers and suffix codes. The location of this code depends on the type of engine, typically as follows: any registrant may be used by WBD for display on any other WBD website without In 68-69 model cars, the serial (VIN) quantity of the car the engine was set up in is stamped next to, or under the engine code ID. but is often erroneously referred to as "Counter Engine", "Counter You may also find it located on the flat block just above the timing cover (in some truck or marine blocks). On a small block GM V8, it is stamped in front of the cylinder head on the passenger side. Some have already been mentioned throughout this article and others are listed here as well. The Small Block Chevrolet engine is one of, if not the most successful engines of all times. They also show the date of assembly and the vehicle model in which the engine was installed. The CE block stamp year is the year the block For example, the Chevy engine VIN 17N012345 means; Another example of the engine VIN is 13N100001 which means: The assembly plant information is denoted by the third letter, which can be a number in some vehicle models. done. Big block on the right side of engine above the oil pan rails. individual character often resulting in some very strange looking engine and see if it matches the vehicle, and if the code signifies Z28 or SS equipment. the plant would re-use the numbers using the letter "A" after Big Block Chevy: Machined pad in front of the passenger side cylinder head or above timing chain cover. one produced in 1971 at Tonawanda with engine serial number 73170. V8 codes are stamped on a pad just forward of the right side (passenger) cylinder head. Exchange" and "Crate Engine" was used on blocks that for Chevrolet Case or "CT" for Chevrolet Transmission. could have happend (or not happened). The suffix portion tells you the original application, vehicle model, engine RPO/ transmission / horsepower, etc found above the timing cover mating surface on the front of the block. The engine assembly date must precede the car build date (often by a few days), otherwise something is amiss. Blue Seal Certified Author of auto/truck repair information. assigned the sequence range of 50,000 to 79,999 so if more engines were - body id plate Beginning in late 1969 model year, 3-letter engine suffix codes were The engines VIN is important to some, since its matching with the cars VIN would mean the engine is the original one that came with the vehicle. These blocks are referred to as the "Gen I" small-block, the subsequent "Gen II" LT, and "Generation III/IV" LS, along with the current "Generation V" (LT/EcoTec3) engines. was added to the partial VIN. assured the partial VIN stamp was uniformly done from car to car. Call 800.979.0122, 7am-10pm, everyday. - Prototypes Here you can clearly see the CE173170 stamping on the engine pad. A0198005 (A = january, 01, 9800 = pn, 5 = 1985). Often hidden by the alterator. the source, production date, and same type designation as stamped on Below is the meaning of each of the letters and numbers in the engine serial number: The first five digits are called the prefix and contain the details about the engine assembly factory, the month in which the assembly was made, and the specific day of the assembly. What we have left is the "suffix code" which in this found above the timing cover mating surface on the front of the block. The motor was assembled Below is a summary chart of the four types of stamping numbers on any Chevy small-block or big-block engine. number, model year, assembly plant designation and vehicle serial or sequence number. This Block Carries A GM Goodwrench 350 Crate Engine Casting Number. Starting in 1970, the serial number is stamped either above the oil filter, somewhere on the block It doesn't indicate what the original equipment was. Chevy smallblock and big block cylinder heads have the CASTING NUMBER and the CASTING DATE located in the rocker arm valley. V8 codes are stamped on a pad just forward of the right side (passenger) This match is done via the PARTIAL VIN stamp on the component. Sometimes (but not always) the letter "I" . example, 6A174373 decodes to 1966 Atlanta final assembly, and the last rough cast area next to the oil filter and sometimes the stamping is L99 vs. LS3 vs. LS7: Which Is The Best Engine For You? That means there are literally millions of these Small Blocks out there. CTG - in 1970. RPO ZQ3, 300hp 350 in a Corvette. VIN Code Format or affixing an identifying number or symbol on major parts. These will have a stamp something like "CC" example, 6A174373 decodes to 1966 Atlanta final assembly, and the last example is ED, a 1966 396cid/325hp for a manual transmission. assembly date and ID letters. required the numbering would start over again at 50,000 but the "CE" The prefix portionof the ID code tells you the engine assembly plant code, and the engines assembly date (for example, 0701 = July 1st.no year is indicated). VIN Code Format otherwise - it's not. by the oil filter. These engines offered great performance with increased horsepower over the standard equipped 350 motors. boss or on the bellhousing flange), most plants for most years did stamp You have remained in right site to begin getting this info. that can help you to determine not only the displacement and horsepower level, but original assembly line application, and more. one produced in 1971 at Tonawanda with engine serial number 73170. 1st day of the month. You can usually determine the correct code (they have been reused over time) by decoding the partial VIN for the model year and/or the casting date found on the rear of the block adjacent to the block casting number. If it doesn't match - is it correct? All engines are stamped with an ID number showing plant code, assembly date, and suffix code. stamped character was placed in a holder and secured before the engine What we have left is the "suffix code" which in this 1973 - eliminates every other possiblity. Submitted photos by The engine assembly code looks similar to this: T0601ED. For example, select "DTR-HQ" if you'd like to find code DZ. The engine assembly day code can either be one or two digits, totally dependent on the actual day of the month the engine was built. CE stamping 073690 from 1970 and date stamped T109. These codes are great to have on hand when shopping at the local swap meet or salvage yard as well. //Random iframe content- Dynamic Drive (www.dynamicdrive.com) the General Motors division (Chevrolet's number is "1"), followed compensation. Some other Chevy models will include the date code on the driver side ledge, especially on the recently manufactured blocks. Here you can clearly see the CE951128 stamping on the engine pad. If it codes out as a 1/2 ton application - we can bet money it's only a 2 bolt. Installing Performance Exhaust Installing a performance exhaust is a popular and rewarding upgrade. nice clean LT1 in a 1971 Corvette under Warranty. same information about partial VINs on engine blocks also applies to It's important to note that This topic can be somewhat confusing, especially with the amount of information available and the interpretation of it. All these are identified here. HOWEVER - the engine code MAY HINT at this fact. For a list of assembly plants, click For help go to engine Code help or engine decoding FAQ. In this case the first letter "T" stands The optional four-barrel carburetor gives 180 horsepower and 260 lb-ft of torque. Another example: A Targetmaster engine (p/n 14009800) built in 1985 could have a code stamped as follows: stamped at the final assembly plant. For example the casting number 140029 will tell you that it was made between 1980 and 1985 and that its a 350 cubic-inch engine. If you're trying to buy a 350 and you see this thing laying on the ground, then there it is. Specific numbers identified the time period it was built and its horsepower range. TR6060 vs. T56 Magnum vs. CD009 vs. TKO600: Which Is The Best? All engines are stamped with an engine ID code, consisting of assembly plant code, production Our Mopar flexplate buyers guide will help. There are over 1300 pages and 8500 images Some had better heads, more compression, or even more cubic inches. Here T099 represents Tonawanda (T), September (09), 1969 (9), Warranty engines will be date stamped on the starter mount pad. The vin code format is stamped onto most engines. Speedway Tech Talk - Tru-Ram Exhaust Manifolds, Small Block and Big Block Chevy Engine Flexplate Guide, Ford And Chevy Spindle Options For Solid Axle Hot Rods, Built With Speedway Motors: Bob's 1936 Chevy Coupe. This list of codes is a summarization, it is not complete nor all inclusive. It's been reported that beginning in 1970, if more engines were needed Operates automotive equipment including electrical (scopes, DMMs, and logic probes), drivability (including scan tools and programming capabilities), alignment, brakes, HVAC, engines, and automatic transmissions. But numbers correct is not numbers matching. done. Dipstick is in the oil pan. A CE number indicates a complete engine, or perhaps a short block. (or in this case a Flint engine plant stamp) was used to 'gang' the links. The engine code and partial vin # will accurately nail down whatever the thing is rather quickly, and the other information will fall into line with that. assigned the sequence range of 50,000 to 79,999 so if more engines were You can also find the date code situated on the passenger side of the block near the freeze plug (in some earlier production blocks from the 60s). //This credit MUST stay intact for use Block casting dates are alpha-numeric, where the first character is a letter that equates to the casting month followed by a one or two digit day code and a single or two digit year code. history By Year (1964-1972). The engine VIN also contains six digits that are used to denote the last six digits of the vehicles VIN. The partial VIN will match the vehicles VIN. The engine ID code, on the other hand, is not a raised part of the casting but an actual stamping into a machined pad. model year, a letter for the final assembly plant, and followed by the //For full source code, and Terms Of use, visit http://dynamicdrive.com would be stamped with a partial VIN consisting of a single number for The plant, date, and engine ID codes were stamped at the respective This topic can be somewhat confusing, especially with the amount of information available and the interpretation of it. The GM division number ('1' for Chevrolet) The suffix portion tells you the original application, vehicle model, engine RPO/ transmission / horsepower, etc - Exports //Specify random URLs to display inside iframe 7- Either 1967 or 1977. Dale Not to say mistakes weren't made as the person responsible had to the "CE" and year designation. - trim codes Again, it either matches or it doesn't. Of the thousands of available suffix codes, this one shows four possible applications, ranging from a 1975 Camaro with 155HP to a 1980 Z-28 with 190 HP. was added to the partial VIN. The Chevy big/small-block engine VIN is located at the front passenger side of the block right next to cylinder #2. Before a federal mandate that all engine blocks be stamped with a LS-5 & LS-6, Corvette 270, 365, 390 & 425 HP with and without A.I.R. compliance of identifying major parts of a motor vehicle by inscribing //Specify IFRAME display attributes or it doesn't. Are you looking to have the information of your SBC or BBC engine using casting numbers? function random_iframe(){ Engine ID Code: V0801CML (This ID is completely made up), An Early Chevy Small Block Casting Date Code, Chevy Engine Casting Numbers Decoding Help. Quickly, A = Chevelle, F = Camaro, X = Nova. after the 1975 model year. For our example shown here this casting number denotes a 350 cubic inch Goodwrench crate engine with a 2-piece rear main seal. Luckily its pretty easy to determine exactly what SBC you have under the hood of your ride. replacement for any number of years' engines, applications, and for The digit denoting the month is usually a letter between A and L but can include numerical numbers in some instances, with 1 indicating January and 12 indicating December. The entire engine Code contains the assembly plant, month and day along with the engine suffix Code. assembly date and ID letters. var iframeprops='width=950 height=250 marginwidth="0" marginheight="0" hspace="0" vspace="0" frameborder="0" scrolling="no"' 45 years in auto/truck industry. 2014 2018 Impala Water in Trunk: Why, What to Do? Blue Seal Certified Author of auto/truck repair information. A Chevy engine serial number is a unique ESN (electronic serial number) used to identify every Chevy vehicle. You need to decode the engine Casting Clock //No need to edit after here How to Reset an Anti-Theft Radio on a What Is the Average Gas Mileage for a "1967 Chevrolet" is Copyrighted by Flickr user: Hugo90 (JOHN LLOYD) under the Creative Commons Attribution license. The "CE" next to, or under the engine code ID. E.g. Often hidden by the alterator. Casting Date (for example, CTY = 1970 396 Camaro, 375 hp, 11.0:1, TH400). You might see something like this "CE056789" Often hidden by the alterator. My point here I guess is trying to decode "3970010" is almost pointless. This is located on a ledge found at the rear of the block, most often on General Decoding Information Casting Date Example: E038 (E = Month, 03 = Day, 8 = Last digit of model year (1978)). Date/Suffix Code: In this episode, Zach and Joe discuss the swap and go for a drive to try it out. While 6 different bore size blocks have been produced, the small block engine can be classified into 3 bore sizes and 3 main bearing sizes. date and suffix code. It can be done on any 3970010 (or other) block. This A Typical Small Block Chevy Casting Number, The Chevy Engine ID Code Features A Prefix And Suffix Code That Provides Key Engine Specs. Big block on the right side of engine above the oil pan rails. Month: A = Jan, B = Feb, C = Mar, D = Apr, E = May, F = Jun, G = July, H = Aug, I =Sep, J = Oct, K = Nov, L = Dec. Notes (for below):"High Power" is the maximum rate HP this block was used for, "Low Power" is the lowest rated horsepower RPO engine the block was used in. However, on the big-block V8 engine, the serial number is located on the cover around the timing belt. A select amount of early small blocks may even have the casting date on the left side of the block casting. ENGINE CODE STAMPING NUMBER All engines are stamped with an engine ID code, consisting of assembly plant code, production date and suffix code. Suffix codes are R, RA, S, SA, RB, K, SB and SG, with each suffix denoting the type of carburetor, transmission and whether the Chevy is equipped with air conditioning. And they are less important when youre trying to quickly see if its a 283 cubic inch motor or 400 cubic inch. TR6060 vs. T56 Magnum vs. CD009 vs. TKO600: Which Is The Best? randomcontent[2]="http://www.chevellestuff.net/sidebar/random03.htm" In 1968 the main bearing saddles were increased in size from 2.3" to 2.45". Required fields are marked *. 14088552, Type your crankshaft casting number in the SEARCH BOX below. at a given plant in a year than the range of sequence numbers allotted, E.g. like this was not mandated but was voluntary to comply as long as they Below is a summary of all the letters and numbers that point to the specific assembly plants. 1970 Atlanta example of the partial VIN stamped on the engine pad. Over the course of 50 years there were many different versions made. is used for McKinnon Industries while "S" pads. General Decoding Information When people say "It's numbers matching" - what they mean is the engine (or other component, i.e the transmission) can be MATCHED to the vehicle it was ledge forms the mating surface between the block and the transmission for "Title 49, United States Code, Subtitle VI, Part C, Chapter far as research has shown, Chevrolet did comply. Even If you already know what you're doing, Chevy Engine Codes are listed down below. In 1987 CLJ is a 305 L69 in a monte carlo, or in 1971 it's a 400 from a Lets find out! The engine assembly code looks similar to this: T0601ED. But if you want to know EXACTLY what if (ie||dom){ vehicle identification The "CE" Quoting from the Chevrolet Dealer Service Information Bulletin, 69-I-1, . being individually stamped. Learn about performing an LS Swap in a 1972 Chevelle in this tech article. An adaptable, detail-oriented, world-class automotive technician with a demonstrated track record of experience in product/technical support, automotive shop management, diagnostics, root cause analysis, maintenance/repairs, quality assurance, customer service, training and mentoring, and staff supervision. 1- Chevrolet. with a partial VIN. L99 vs. LS3 vs. LS7: Which Is The Best Engine For You? 24502572, Type your crankshaft casting number in the SEARCH BOX below. It's a 350. This is the "CE" This It was found inside the original plywood crate, exactly how it was purchased from Chevrolet and. In honor of Presidents Day, celebrate all week long and save some Benjamins with Free Shipping* on orders over $199. domain names and wishing to carry on the ChevelleStuff tradition of bringing Transmissions were also subject to replacement, be it just the case Engine Code Stamping Numbers I think the casting number should be 3969854which is a 69-72 396/402. 7 Absolute Best Carburetors for Chevy 350 in 2023 [Review]. Abbreviations: A.I.R. 7017300R, SBC Head Casting Numbers: Full List & Lookup, I have a customer that has a small block chevy motor with 2 numbers on the block as follows V0311CLK. Small Block Chevy Stamping Numbers The prefix portion of the ID code tells you the engine assembly plant code, and the engine's assembly date (for example, 0701 = July 1st.no year is indicated). This series of seven to eight digits begins with a letter and is stamped directly on the engine. document.write('') For example, in the small-block V8 engine, the serial number is located on the passenger side of the engines cylinder heads. on the front pad of the block deck on the passenger side. C5s181710 In 1968 the main bearing saddles were increased in size from 2.3" to 2.45". 14094065, Type your intake manifold number in the SEARCH BOX below. But numbers correct is not numbers matching. details accurate. However, a properly prepared 2 bolt main engine will work just fine (often times you'll lose a rod bolt before you break a crank because it's "only" a 2 bolt main). They mandated this format in 1972 after abolishing a longer form that used letters like NOR to show Norwood instead of the current N for Norwood. Reading section All engines are stamped with an engine ID code, consisting of assembly plant code, production date and suffix code. stating, "Starting in 1967 for the 1968 model year, Ford began Our sample block casting date in the photo at left is I 9 57, which would decode as September 9, 1957 (as found on a 1958 348 small block). Morec1@aol.com. If you want more specific information, you have to look at the Stamped Numbers. for any legitimate purpose on this and other websites in the Webs By Dale - Exports please note the exact page by its address Sling Ray Car: What Makes This Car One of a Kind? The "DB" on the end of the engine code does represent a Chevy small block 283ci 230hp with Powerglide . This website is the And you can check dates. Select the portion of the alphabet for your code. MoPar forums searched seem to indicate that MoPar didn't follow the is used for McKinnon Industries while "S" This list of codes is a summarization, it is not complete nor all inclusive. Stamped Numbers are a set of numbers literally stamped into the block. The engine date must precede the car build date, otherwise something is amiss. I have no idea. drilling the holes is a machining operation. be for 1968 and later. ton application, or some high powered application, you can ASSUME it might just be a 4 bolt main. as follows: code. sole property of WBD. Their casting info includes cylinder heads, crankshafts, and more, besides the small and big block engine block casting details we've mentioned in this guide. The engine code and partial vin # will accurately nail down whatever the thing is rather quickly, and the other information will fall into line with that. Therefore the two stampings will But numbers correct is not numbers matching. General Motors standardized this procedure by using what's called Lastly, in extreme cases, you'll want to verify the numbers stamped onto the component were the ones stamped into it originally and aren't restamped. letter "A" was added to note the rollover. Again, engine that was stamped "CE" with a 6-digit number following Date codes consists of a letter, 1 or 2 digits for the day, and 1 // window.onload=random_iframe, Webs By is strictly prohibited by law. originally used in. Generally, you can find the engine VIN stamped next to the engine ID code or below it. In other vehicles, you may find the serial number located on the flat block just above the timing cover (in some trucks or marine blocks.). http://uscode.house.gov/download/pls/49C331.txt or search the Internet Can you tell me what year this engine is VF292800- is an example of a over the counter crate engine. All engines are stamped with an engine ID code which consists of a prefix and a suffix. The "01" stands for the And you can check dates. number. a 1976 dated Chevrolet parts book, "The engine plants ht used on the engine pad. stamp could be applied. Take a truck 350. The primary pieces of information you'll decode are the Engine Code and Partial VIN. "Numbers Matching" Strong background in facilitating adult education including analysis, design, development, implementation, and evaluation of training programs. randomcontent[1]="http://chevellestuff.net/sidebar/random02.htm" The engine could use a stock 426 Hemi block, but the block that was used had none of the machining done for the lifters or any other associated pieces. Numbers matching is important when you're trying to decode a Z28 or Super Sport where the VIN won't identify the vehicle as such. get the 283 Small Block Chevy Engine Codes connect that we allow here Chevelle and Passenger with and without A.I.R. The first one I usually use is the block casting number which is located at the back of the driver's side cylinder head and will look something like: 3970010. This match is done via the PARTIAL VIN stamp on the component. It is common on these later blocks to see "5.0L" or "5.7L". They are located on the drivers side rear of the block on the flange forward of the bellhousing. It is essential to distinguish the engines VIN from the vehicles VIN since they are different numbers. Decode small block Chevy engine suffix codes with our SBC casting. - vin VIN Code beside the engine pad (such as the rough cast area by the oil filter - compliance Plate rough cast area next to the oil filter and sometimes the stamping is During this timeframe, this was either a 307 or 350 engine. VIN code format Example: 13N100001 The bottom line is that it's a 3.48-inch stroke, helping us to determine that our engine is a 350. Casting Date Example: E038 - (E = Month, 03 = Day, 8 = Last digit of model year (1978)). E.g. These two numbers are the casting number and engine ID code. - gmh dealer codes models this date is accurate for federal mandate that engine blocks be stamped "Numbers Matching" An adaptable, detail-oriented, world-class automotive technician with a demonstrated track record of experience in product/technical support, automotive shop management, diagnostics, root cause analysis, maintenance/repairs, quality assurance, customer service, training and mentoring, and staff supervision. if (ie||dom){ Month: A = Jan, B = Feb, C = Mar, D = Apr, E = May, F = Jun, G = July, H = Aug, I = Sep, J = Oct, K = Nov, L = Dec, Chevy Small Block - Engine Block Casting Numbers, QUICKLY IDENTIFY A CHEVY ENGINE CLICK HERE, Click here for Chevy Engine Code Listings. It represents any CID and is used to indicate this particular engine was replaced under Warranty. Car & Truck 2-bolt Passenger stick 1-piece seal, 2 & 4-Bolt Passenger stick 1-Piece seal Roller cam, Car & Truck 2 & 4-bolt Passenger stick 1-piece seal, 2-bolt Truck Passenger stick 1-piece seal, 2-bolt Roller cam Passenger stick 1-piece seal, car & Truck 2-bolt Passenger stick After 79, Camaro/firebird 2 & 4-bolt LT-1 Reverse cooling Roller cam, Car and Truck 2 & 4-bolt 1 Piece Seal Passenger stick, Chevelle, Camaro, Monte Carlo and Passenger. website and domain name plus ChevelleStuff.com domain name are for sale. for an engine factory Tonawanda Engine Plant, either "F" Courtesy Todd Burke, A calendar year 1973 replacement engine #356957, A calendar year 1973 replacement engine #367742, Warranty engines will be date stamped on the starter mount pad. have different fonts, character sizes, and in some cases will be stamped stamped. Copyrighted 2002-2017, this date is accurate for federal mandate that engine blocks be stamped A 1968 version of an Atlanta partial VIN on all engine blocks(1). Specific numbers identified the time period it was built and its horsepower range. other pieces and parts should have been on it, and check those casting #'s. Some engine machining operations (decking) will obliterate the engine ID. not start until 1968 so any year designation in the engine number would After being stored away for decades, Bob finally finished his big block powered '36 Chevy coupe Having issues fitting headers into your car/engine? Your email address will not be published. or the entire transmission. Thanks, Lots of good info. The next two digits stand for the month stamped at the final assembly plant. This is the "CE" VIN Code Format A CE engine is a warranty replacement or an engine that was bought from the parts department. The same applies as for the block casting numbers, they will be hard to see with the engine still in the truck. Another CE stamping, this one is 066953 from 1970. engine assembly plants while the partial VINs (when applicable) were Engine Assembly When people say "It's numbers matching" - what they mean is the engine (or other component, i.e the transmission) can be MATCHED to the vehicle it was Bonus: SBC BBC V6 Chevy Engines Specs and Sizes [With Chart]. } Well show you what to look for in this buyers guide. 6 cylinder engines are stamped on the passenger side of the block behind the the most accurate and up to date information to the Chevelle community can being individually stamped. Transmissions were also subject to replacement, be it just the case Not only do you get more performance out of your engine, you, Classic Consoles Sale Start Shopping Below Regal Chevelle Camaro El Camino Malibu Monte Carlo Nova Cutlass Grand Prix. VIN code format Example: 13N100001 Proven aptitude for maximizing customer satisfaction and ensuring safety/compliance. ledge forms the mating surface between the block and the transmission the plant would re-use the numbers using the letter "A" after hk Does that meaning anything to you that will Id the engine? You might see something like this "CE056789" While the engine ID will not always tell the story on a service block or crate engine, the casting number still will. This post provides you with a detailed explanation about stamping numbers on a GM/Chevy engine. code. SBC BBC V6 Chevy Engines Specs and Sizes [With Chart], Chevy Big/Small Block Casting Numbers Lookup. home replacement for any number of years' engines, applications, and for Often hidden by the alterator. Corvette 300, 330, 350 & 370 HP 2.0" Outlet A.I.R. Want to know exactly what you have? The prefix portion of the ID code tells you the engine assembly plant code, and the engine's assembly Here's your chance, click below to see what positions are opening soon! Wagner attended California State University, Los Angeles, and has a degree in journalism. far as research has shown, Chevrolet did comply. The CE block stamp year is the year the block This is why I looked at the VIN code 1st. This ledge is below the deck of the block and the ledge forms the mating surface between the block and the transmission bellhousing. vx What's this A/F/X stuff? // window.onload=random_iframe, Mac's Leave a comment at the end of this post if you cannot find the information you want. The partial VIN consisted of a single number representing the